This invention relates generally to hydraulic valves and particularly directed to the testing of solenoid-actuated hydraulic valves.
Closed hydraulic control systems include hydraulic valves, or switches, for controlling the flow of hydraulic fluid within the system. These hydraulic valves typically include a solenoid and are responsive to electrical signals for opening and closing of the valve. Each valve is rated to withstand a specified pressure. It is desirable to verify operation of the hydraulic valve up to this specified pressure under operating conditions prior to installation in the hydraulic control system. U.S. Pat. No. 4,854,165 to Jay discloses apparatus for testing an electrical switch responsive to fluid under pressure, wherein the testing apparatus simulates current loads experienced by the switch during operation. The testing apparatus also includes a meter communicating with the flow of fluid under pressure indicating whether a solenoid valve is operating properly. This apparatus is not a stand-alone device in that it requires a source of hydraulic fluid and a pressure source.
U.S. Pat. No. 4,903,529 to Hodge discloses an arrangement for testing a hydraulic device of a hydraulic control system by disconnecting the device from the control system and connecting it to a valve system analyzer which applies hydraulic fluid under pressure to the device. The fluid under pressure is monitored to evaluate operation of the device. This approach allows for testing the components of a hydraulic control system without removal from the system such as during scheduled shut-down periods. As such, this approach does not provide for testing and verification of proper operation of a hydraulic device under operating conditions prior to installation in the hydraulic control system.
The present invention addresses the aforementioned limitations of the prior art by providing apparatus for the complete testing of a hydraulic valve under operating conditions prior to installation in a hydraulic control system. A solenoid-actuated hydraulic valve is tested while energized, or open, so that fluid flow is in a first direction in the apparatus, and while deactivated, or closed, with fluid flow in a second, opposite direction. Pressure is easily and accurately measured by a pair of pressure gauges disposed adjacent to and on respective sides of a manually setable needle valve set at the hydraulic valve's rating.